This invention relates to an exapandable beam structure formed of a plurality of sides of scissor link members which may be readily extended to erect a beam from a collapsed position for usage.
In the past, there have been many applications of scissor link type structures applied to booms, towers, and supports of varying types. A continuous need for structures of this type, which can be retracted to a very compact configuration for transport and storage and expanded for use, has existed for a long time. Numerous examples of prior patented structures of this general type exist in the prior art. Some typical prior structures, for example, are shown in the following U.S. Pat. Nos. 156,842, 217,439; 1,511,679; 1,947,647; and 3,435,570. All of these prior structures have a point in common in that they have relatively low strength in the extended direction. As such they are not capable of withstanding high load conditions. Further, some of these structures have been made expandable through the use of very complicated extension means, such as centrally located telescopic booms or screw or guide structures to expand the same. The interconnection between the links in such prior structures provide the capability of the extension but fail to provide a structure with any tensile or compressive strength or any means for increasing the strength of the same.